The present invention relates to an inspection method and inspection apparatus for use in a production line for a semiconductor device, liquid crystal, magnetic head, or other device, and more particularly to a technology for inspecting for foreign matters (particle)/defects.
An example of semiconductor wafer inspection will now be described.
In a conventional semiconductor manufacturing process, any foreign matter existing on a semiconductor substrate (wafer) may cause a wiring insulation failure, short circuit, or other failure. Furthermore, since the semiconductor elements have turned minutely, when a fine foreign matter exists in the semiconductor substrate, this foreign matter causes for instance, insulation failure of capacitor or destruction of gate oxide film or etc. These foreign matters are mixed in the semiconductor substrate by various causes in the various state. As a cause of generating of the foreign matters, what is generated from the movable part of conveyance equipment, what is generated from a human body and the thing by which reaction generation was carried out by process gas within processing equipment, the thing currently mixed in medicine or material used can be considered. A liquid-crystal display device will become what cannot be used, if a foreign matter mixes on a circuit pattern or a certain defect produces a liquid-crystal display device manufacturing process similarly. The same also holds true for a printed circuit board manufacturing process so that foreign matter mixture results in a pattern short circuit or improper connection.
A certain conventional technology for detecting the above-mentioned foreign matters (particles) on a semiconductor substrate, which is disclosed, for instance, by Japanese Patent Laid-open No. 62-89336, illuminates laser light to the semiconductor substrate, detects the light scattered from any foreign matter on the semiconductor substrate, and compares the obtained result against the inspection result of the last inspected semiconductor substrate of the same type to conduct a high-sensitivity, high-reliability, foreign matter/defect inspection while averting a pattern-induced false alarm. Another known technology for inspecting for the above-mentioned foreign matter, which is disclosed, for instance, by Japanese Patent Laid-open No. 5-218163, illuminates coherent light to a wafer, eliminates the light emitted from a repetitive pattern on the wafer with a spatial filter, and enhances non-repetitive foreign matter and defects to achieve detection.
Further, there is a known foreign matter inspection apparatus, which illuminates from a direction having an angle of 45 degrees for major straight line group within a circuit pattern formed on a wafer in order to prevent from entering zero-order diffracted light generated from the major line group into an aperture of an objective lens. As regards the technology incorporated in this foreign matter inspection apparatus (see Japanese Patent Laid-open No. 1-117024), a method for shielding diffracted light generated from non-major straight line group with a spatial filter is disclosed. Furthermore, there are many known conventional technologies concerning an apparatus and method for inspecting for foreign matter and other defects (see Japanese Patent Laid-open No. 1-250847, Japanese Patent Laid-open No. 6-258239, Japanese Patent Laid-open No. 6-324003, Japanese Patent Laid-open No. 8-210989, and Japanese Patent Laid-open No. 8-271437).